Development of Integrase Inhibitors of Quinolone Acid Derivatives for Treatment of AIDS: An Overview

Effect of a newly synthesized quinoline-based compound (PPQ-8) on murine schistosomiasis mansoni

Schistosomiasis represents a public health problem and praziquantel is the only drug used for treatment of all forms of the disease. Thus, the development of new anti-schistosomal agents is of utmost importance to increase the effectiveness, reduce side effects and delay the emergence of resistance. The present study was conducted to report the therapeutic efficacy of PPQ-8, a new synthetic quinoline-based compound against Schistosoma mansoni. Mice were treated with PPQ-8 at day 49 post infection using two treatment regimens (20 and 40 mg/kg). Significant reductions were recorded in hepatic (62.9% and 83.6%) and intestinal tissue egg load (57.4% and 73.5%), granuloma count (75.4% and 89.1%) and diameter (26.2% and 47.3%), in response to the drug regimens, respectively. In addition, both treatment regimens induced significant decrease in liver (23.3% and 32.8%) and spleen (37.5% and 45.3%) indices. Also, there were significant reductions in mature ova, total worm and female count, which were more prominent with the higher dose. The reduction in the level of nitric oxide in the liver by both therapeutic regimens to 22.5% and 47.2% indicates the anti-oxidant activity of PPQ-8. Bright field microscopic examination of worms recovered from infected and PPQ-8-treated mice showed nearly empty intestinal caeca with no observable changes in the tegument. Our findings hold promise for the development of a novel anti-schistosomal drug using PPQ-8, but further in vitro and in vivo studies are needed to elucidate the possible mechanism/s of action and to study the effect of PPQ-8 on other human schistosomes.

Dimerization–cyclization reactions of isocyanoaryl-tethered alkylidenecyclobutanes via a triplet biradical mediated process

A triplet biradical mediated dimerization–cyclization reaction of isocyanoaryl-tethered alkylidenecyclobutanes to construct macrocyclic skeletons including dihydroquinoline and quinoline units has been reported.

Total synthesis of quinolactacin-H from marine-derived Penicillium sp. ENP701 and biological activities

The quinolactacins are a family of pyrroloquinoline-type natural products from Penicillium sp. From the organic extract of Penicillium sp. ENP701 fermentation broth, a microorganism from the east China sea, one new quinolactacin was isolated and named quinolactacin-H. The structure of quinolactacin-H was determined by spectroscopic analysis and the absolute configurations by X-ray crystallographic analysis. Enantioselective total synthesis of (R)-(+)-quinolactacin-H and (S)-(−)-quinolactacin-H was achieved. When assayed through crystal violet (CV) microtiter plate biofilm, both (R) and (S)-quinolactacin-H showed a strong inhibition and dispersion of Pseudomonas aeruginosa PAO1 biofilms. Thus, quinolactacins could be proposed and developed as natural anti-bioflm agents in order to solve the problem of microbial resistance in future.

Quinolactacin-H is a new pyrroloquinoline-type natural product isolated from a marine Penicillium sp. ENP701. We total synthesize (R)- and (S)-quinolactacin-H. Both (R)- and (S)-quinolactacin-H show inhibit and disperse Pseudomonas aeruginosa PAO1 biofilms.

Crystal structure, Hirshfeld surface analysis and DFT studies of ethyl 2-{4-[(2-eth-oxy-2-oxoeth-yl)(phen-yl)carbamo-yl]-2-oxo-1,2-di-hydro-quinolin-1-yl}acetate

The title com-pound, C24H24N2O6, consists of ethyl 2-(1,2,3,4-tetra-hydro-2-oxo-quinolin-1-yl)acetate and 4-[(2-eth-oxy-2-oxoeth-yl)(phen-yl)carbomoyl] units, where the oxo-quinoline unit is almost planar and the acetate substituent is nearly perpendicular to its mean plane. In the crystal, C-HOxqn⋯OEthx and C-HPh-yl⋯OCarbx (Oxqn = oxoquinolin, Ethx = eth-oxy, Phyl = phenyl and Carbx = carboxyl-ate) weak hydrogen bonds link the mol-ecules into a three-dimensional network sturucture. A π-π inter-action between the constituent rings of the oxo-quinoline unit, with a centroid-centroid distance of 3.675 (1) Å may further stabilize the structure. Both terminal ethyl groups are disordered over two sets of sites. The ratios of the refined occupanies are 0.821 (8):0.179 (8) and 0.651 (18):0.349 (18). The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (53.9%), H⋯O/O⋯H (28.5%) and H⋯C/C⋯H (11.8%) inter-actions. Weak inter-molecular hydrogen-bond inter-actions and van der Waals inter-actions are the dominant inter-actions in the crystal packing. Density functional theory (DFT) geometric optimized structures at the B3LYP/6-311G(d,p) level are com-pared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO mol-ecular orbital behaviour was elucidated to determine the energy gap.

Crystal structure, Hirshfeld surface analysis and inter-action energy and DFT studies of 2-chloro-ethyl 2-oxo-1-(prop-2-yn-1-yl)-1,2-di-hydro-quinoline-4-carboxyl-ate

The title compound, C15H12ClNO3, consists of a 1,2-di-hydro-quinoline-4-carb-oxyl-ate unit with 2-chloro-ethyl and propynyl substituents, where the quinoline moiety is almost planar and the propynyl substituent is nearly perpendicular to its mean plane. In the crystal, the mol-ecules form zigzag stacks along the a-axis direction through slightly offset π-stacking inter-actions between inversion-related quinoline moieties which are tied together by inter-molecular C-HPrpn-yl⋯OCarbx and C-HChlethy⋯OCarbx (Prpnyl = propynyl, Carbx = carboxyl-ate and Chlethy = chloro-eth-yl) hydrogen bonds. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (29.9%), H⋯O/O⋯H (21.4%), H⋯C/C⋯ H (19.4%), H⋯Cl/Cl⋯H (16.3%) and C⋯C (8.6%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packing. Computational chemistry indicates that in the crystal, the C-HPrpn-yl⋯OCarbx and C-HChlethy⋯OCarbx hydrogen bond energies are 67.1 and 61.7 kJ mol-1, respectively. Density functional theory (DFT) optimized structures at the B3LYP/ 6-311 G(d,p) level are compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.

Recent advances in the synthetic and medicinal perspective of quinolones: A review

In the modern scenario, the quinolone scaffold has emerged as a very potent motif considering its clinical significance. Quinolones possess wide range of pharmacological activities such as anticancer, antibacterial, antifungal, antiprotozoal, antiviral, anti-inflammatory, carbonic anhydrase inhibitory and diuretic activity etc. The versatile synthetic approaches have been successfully applied and several of the resulted synthesized compounds exhibit fascinating biological activities in numerous fields. This has prompted to discover quinolone-based analogues among the researchers due to its great diversity in biological activities. In the past few years, various new, efficient and convenient synthetic approaches (including green chemistry and microwave-assisted synthesis) have been designed and developed to synthesize diverse quinolone-based scaffolds which represent a growing area of interest in academic and industry as well as to explore their biological activities. In this review, an attempt has been made by the authors to summarize (1) One of the most comprehensive listings of quinolone-based drugs or agents in the market or under various stages of clinical development; (2) Recent advances in the synthetic strategies for quinolone derivatives as well as their biological implications including insight of mechanistic studies. (3) Further, the biological data is correlated with structure-activity relationship studies to provide an insight into the rational design of more active agents.

Quinolone derivatives and their antifungal activities: An overview

More than 300 million people suffer from the incidence of life-threatening invasive fungal infections, resulting in over 1.35 million deaths annually. Currently, the antifungal agents available in clinics are rather limited, and the rapid development of resistance to the existing antifungal drugs has further aggravated mortality. Quinolones possess a broad spectrum of chemotherapeutic properties and demonstrate considerable antifungal activities as well. Various quinolone derivatives have been screened for their antifungal activities, and some of them exhibit excellent potency against both drug-susceptible and drug-resistant fungi. This review aims to outline the recent advances in quinolone derivatives as potential antifungal agents and summarize the structure-activity relationship, to provide insights for the rational design of more active candidates.

Fluoroquinolone-isatin hybrids and their biological activities

Hybridization of different pharmacophores from various bioactive substances into a single molecule is the potential weapon to prevent the drug resistance since this strategy can provide new leads with complimentary activities and/or multiple pharmacological targets. Fluoroquinolone and isatin are common pharmacophores, and their derivatives possess various biological activities. Obviously, hybridization of these two pharmacophores into one molecule may result in novel candidates with broader spectrum, higher efficiency, lower toxicity as well as multiple mechanisms of action. Therefore, fluoroquinolone-isatin hybrids have the potential for clinical deployment in the control and eradication of various diseases. This review covers the recent advances of fluoroquinolone-isatin hybrids as potential anti-bacterial, anti-tubercular, anti-viral and anti-cancer agents. The structure-activity relationship is also discussed to pave the way for the further rational development of this kind of hybrids.

Quinolone derivatives and their activities against methicillin-resistant Staphylococcus aureus (MRSA)

Methicillin-resistant Staphylococcus aureus (MRSA) is the most common pathogen both in hospital and community settings, and is capable of causing serious and even fatal infections. Several antibiotics have been approved for the treatment of infections caused by MRSA, but MRSA has already developed resistance to them. More than ever, it's imperative to develop novel, high effective and fast acting anti-MRSA agents. Quinolones are one of the most common antibiotics in clinical practice used to treat various bacterial infections, and some of them displayed excellent in vitro and in vivo anti-MRSA activities, so quinolone derivatives are one of the most promising candidates. This review summarizes the recent developments of quinolone derivatives with potential activity against MRSA, and the structure-activity relationship is also discussed.

3D-QSAR studies of quinoline ring derivatives as HIV-1 integrase inhibitors

In the process of HIV-1 virus replication, integrase plays a quite important role. Integrase inhibitors of quinoline ring derivatives were analysed by the Comparative Molecular Field Analysis (CoMFA), Comparative Molecular Similarity Induces Analysis (CoMSIA) and Topomer CoMFA methods. Firstly, 77 compounds were selected to form the training and test sets. Secondly, predictive models were constructed with the CoMFA, CoMSIA and Topomer CoMFA methods. The CoMFA model yielded the best model with q (2) of 0.76 and [Formula: see text] of 0.99, the CoMSIA model has q (2 )= 0.70 and [Formula: see text] of 0.99, while the Topomer CoMFA model has q (2) of 0.66 and [Formula: see text] of 0.97. These results provide a helpful contribution to the design of novel highly active HIV-1 integrase inhibitors.